Tissue-acquisition device and method

ABSTRACT

Described herein is an improved device and method for acquiring, and optionally, fastening a tissue fold. The device has an improved configuration for forming a single, two-layer tissue fold.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/740,129, filed Jan. 11, 2013, which claims priority to U.S. patentapplication Ser. No. 61/586,657, filed on Jan. 13, 2012. Each of theabove-referenced applications is incorporated herein by reference in itsentirety.

FIELD OF THE INVENTION

The present invention relates generally to the field of a device andmethod for acquiring, and optionally, fastening a tissue fold.

BACKGROUND OF THE INVENTION

One of the current methods of treating obesity is to reduce stomachvolume by forming extended and/or multiple two-layer tissue folds in thestomach. Ideally, the method is carried so that up to one half or moreof the original area of the stomach interior is sequestered in tissuefolds, reducing both the volume of the stomach and area within thestomach that can interact with ingested food. This approach has thegeneral advantages in treating obesity that (i) it is non-invasive inthat it is carried out using an intra-oral stapling procedure; (ii)stomach volume can readily reduced by a desired amount, e.g., between50-80 percent, according to the number and sizes of folds formed, (iii)the tissue folds may be formed in areas of the stomach, e.g., thefundus, that are especially susceptible to appetite control, and (iv)the procedure can be readily repaired or fine-tuned by simply by formingadditional tissue folds as needed in one or more follow-up procedures.

Devices designed for treating obesity and/or gastroesophageal refluxdisease (GERD) by forming stomach plications are known, e.g., U.S. Pat.Nos. 5,571,116, 5,887,594, 6,113,609, 6,159,146, and 6,592,596. SeveralU.S. Patents, including U.S. Pat. No. 6,663,639, and related U.S. Pat.Nos. 6,494,888, 6,773,441 and 7,736,373 disclose endoscopic methods ofreconfiguring the stomach by manipulating two or more separate tissuefolds. Similar methods for reconfiguring the stomach by bringingtogether two or more tissue folds are disclosed in U.S. Pat. No.6,558,400, and related U.S. Pat. Nos. 7,288,099, 7,288,101, 7,510,559,U.S. 7,503,922, and 7,862,574. U.S. Pat. No. 7,175,638 also disclosesand claims reconfiguring the stomach by forming pairs of tissue folds,i.e., one or more four-layer folds.

Co-owned U.S. Pat. Nos. 7,708,181, 7,721,932, 7,909,219, 7,909,222,7,909,223, 7,913,892, 7,922,062, 7,934,631, and 8,020,741 disclose adevice for forming and stapling tissue folds in the stomach. The deviceincludes staple and anvil members that are operable to move toward andaway from one another along a first axis, and arm assemblies connectingthe two members and that expand outwardly, along a second axissubstantially perpendicular to the first axis, as the proximal anddistal members move toward one another to a tissue-capture position. Theconfronting faces of the two members and the arm assemblies connectingthem define a tissue-capture chamber that is covered by the by aflexible-membrane sleeve having an opening through which tissue is drawnwhen the opening is placed against tissue and a vacuum is applied to thechamber. The device has a low-profile in a relaxed mode, for intra-oralinsertion, and expands outwardly, during operation, to allow arelatively large two-layer tissue fold to be drawn into the chamber.Once a tissue fold is captured in the chamber, the device may beoperated to place a ring of staples through the fold and, optionally, toform a cutout in the tissue fold within the ring of staples. Onelimitation of the device that has been observed, however, is that morethan two layers of tissue may be drawn into the chamber, during vacuumuptake, and/or that a portion of the flexible-membrane sleeve thatsurround the sleeve opening may itself be drawn into the chamber, andstapled to the tissue fold.

It would thus be desirable to provide an improved device for forming atissue fold, e.g., within the stomach, which has the advantages of theabove-described device, but overcomes the current limitations in tissueuptake.

SUMMARY OF THE INVENTION

In one aspect, the invention includes an improvement in a device forforming a tissue fold composed of two tissue layers, by drawing tissueinto a tissue chamber in the device through an opening in aflexible-membrane sleeve that covers the tissue chamber, upon theapplication of a vacuum to the chamber when the sleeve opening is placedagainst tissue. The improvement comprises a sleeve opening in the formof an elongate slit having a gap dimensioned to restrict intake throughthe slit of additional tissue layers, once the two tissue layers of thetissue fold have been drawn into the tissue chamber through the slit.

The gap in the slit may be dimensioned to maintain the two layers of atissue fold in contact with one another as they are being drawn into thetissue chamber through the slit. The gap, in the relaxed state of thesleeve, may be between 10 and 200 mils.

The sleeve may be formed of silicon having a durometer hardness ofbetween 25-35 Shore A and a membrane thickness of between 20-50 mils.The sleeve may have a reinforcing lip about the slit to aid insupporting the slit as tissue is being drawn through the slit under avacuum.

The device may operate to stretch the slit in a lengthwise direction,during application of vacuum to the chamber, and the gap in the slit mayremain dimensioned to restrict intake through the slit of additionaltissue layers, once the two tissue layers of the tissue fold have beendrawn into the tissue chamber through the slit, as the slit is stretchedin a lengthwise direction. The slit may have a lengthwise dimension, ina relaxed state, of between about 10-15 mm, and in a fully stretchstate, between 25-50 mm.

The improved device may further include a reservoir connecting thetissue chamber in the device to a vacuum source, for modulating the rateat which vacuum is applied to the device chamber from the vacuum source.

In one general embodiment, the tissue chamber in the device is definedby (i) confronting faces of proximal and distal members that areoperable to move toward and away from one another along a first axis,(ii) arm assemblies connecting the two members and that expandoutwardly, along a second axis substantially perpendicular to the firstaxis, as the proximal and distal members move toward one another to atissue-capture position, and (iii) the flexible-membrane sleeve coveringat least portions of said two members and having an intermediate portioncovering said chamber. Here the sleeve slit is oriented lengthwise inthe direction of said second axis, such that movement of the armassemblies outwardly, as the two members are moved toward one another,acts to stretch said slit in a lengthwise direction.

In this embodiment, the sleeve may include reinforcing plates disposedon either side of said slit and extending axially in the direction ofthe movement of the associated proximal or distal members, and beingsupported thereon, to resist forces on the slit in the direction oftissue intake. The interior surface of said sleeve may have one or moreslots extending axially along the direction of travel of the twomembers, to maintain a vacuum connection within the chamber as a tissuefold presses against said interior surface during acquisition of atissue fold. At least one of the arm assemblies may include an elbowthat defines a nubbin slot, and the interior surface of the sleeve mayinclude at least one nubbin that is received in an associated nubbinslot, when the sleeve is properly positioned on proximal and distalmembers of the device, to retain the sleeve in place when the assemblyarms are expanded and the sleeve is stretched along the second axis.This embodiment of the device may include a staple cartridge and stapledriver in one housing, a staple anvil in the other housing, and ahydraulic line by which the staple cartridge can be activated, when atissue fold is captured in the device, to fasten the fold with one ormore staples.

In another aspect, the invention includes an improvement in a method forforming a tissue fold composed of two tissue layers, by drawing tissueinto a tissue chamber through an opening in a flexible-membrane sleeve,upon the application of a vacuum to the chamber when the opening placedagainst tissue. The improvement includes the steps of

(a) placing against the tissue, a flexible-membrane sleeve whose openingis an elongate slit having a gap dimensioned to restrict intake throughthe slit of additional tissue layers; once the two tissue layers of thetissue fold have been drawn into the tissue chamber through the slit;and(b) applying to the chamber, a vacuum that increases in a controlledmanner as tissue is being drawn into the chamber.

The sleeve's elongate slit that is positioned against the tissue in step(a) may be dimensioned to maintain the layers of a tissue fold incontact with one another as they are being drawn into the tissue chamberthrough the slit. The slit may have a width, in the relaxed state of thesleeve, of between 20 to 125 mils.

The improvement method may further include during applying step (b),stretching the slit in a lengthwise direction, and step (b) may becarried out such that a maximum vacuum in the vacuum chamber is reachedafter the slit has been fully stretched. Step (b) may be carried out byapplying a vacuum to a reservoir bottle that is connected to the tissuechamber.

Also disclosed is an apparatus for forming a tissue fold composed of twotissue layers, comprising (a) a device having a tissue chamber coveredby a flexible-membrane sleeve, the sleeve having an elongate slit with agap dimensioned to restrict intake through the slit of additional tissuelayers, once the two tissue layers of the tissue fold have been drawninto the tissue chamber through the slit, under a vacuum applied to thechamber; (b) a vacuum source for applying vacuum to said chamber; and(c) a controller operatively connected to said vacuum source forcontrolling the rate at which vacuum is applied to said chamber, tocontrol the rate at which tissue is drawn into said chamber.

As above, the gap in the slit may be dimensioned to maintain the twolayers of a tissue fold in contact with one another as they are beingdrawn into the tissue chamber through the slit, and in the relaxed stateof the sleeve, may be between 40 and 125 mils.

The controller in the apparatus may be a reservoir bottle operativelyconnecting the vacuum source to the vacuum chamber.

The device may operate to stretch the slit lengthwise as the controlleris controlling the rate of vacuum being formed in said chamber.

In one general embodiment, the device includes a tissue chamber definedby (i) confronting faces of proximal and distal members that areoperable to move toward and away from one another along a first axis,(ii) arm assemblies connecting the two members and that expandoutwardly, along a second axis substantially perpendicular to the firstaxis, as the proximal and distal members move toward one another to atissue-capture position, and (iii) the flexible-membrane sleeve coveringat least portions of said two members and having an intermediate portioncovering said chamber, and wherein the slit in the sleeve is orientedlengthwise in the direction of said second axis, such that movement ofthe arm assemblies outwardly, as the two members are moved toward oneanother, acts to stretch said slit in a lengthwise direction.

The sleeve in this embodiment may include reinforcing plates disposed oneither side of said slit and extending axially in the direction of themovement of the associated proximal or distal members, and beingsupported thereon, to resist forces on the slit in the direction oftissue intake. The interior surface of the sleeve may have one or moreslots extending axially along the direction of travel of the twomembers, to maintain a vacuum connection within the chamber as a tissuefold presses against said interior surface during acquisition of atissue fold. At least one arm assembly may include an elbow that definesa nubbin slot, and the interior surface of the sleeve may include atleast one nubbin that is received in an associated nubbin slot, when thesleeve is properly positioned on proximal and distal members of thedevice, to retain the sleeve in place when the assembly arms areexpanded and the sleeve is stretched along the second axis.

The device may include a staple cartridge and staple driver in onehousing, a staple anvil in the other housing, and a hydraulic line bywhich the staple cartridge can be activated, when a tissue fold iscaptured in the device, to fasten the fold with one or more staples.

The controller may be a reservoir bottle operatively connecting thevacuum source to the vacuum chamber.

These and other objects and features of the invention will become morefully apparent when the following detailed description of the inventionis read in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic illustration of a human stomach and a portion ofthe small intestine, as known in the prior art.

FIG. 1B is a cross-sectional perspective view of a portion of a stomachwall, illustrating the layers of tissue forming the wall, also as knownin the prior art.

FIG. 2 illustrates an endoscopic tissue-fold and stapling system anddevice constructed in accordance with an embodiment of the invention.

FIGS. 3A-3C are perspective views showing the tissue-fold and staplingdevice of the stapling system of FIG. 2 in three different positions;

FIGS. 4A-4C are top plan views of the tissue-capture and stapling deviceFIG. 3, showing the device in its low-profile condition (4A), duringtravel of the staple and anvil members toward a tissue-capture condition(4B), and the device in its tissue-capture condition (4C);

FIG. 5 is a perspective view of the device in its FIG. 4C condition,showing the positions of the arm assemblies and membrane raiser in thetissue-capture condition;

FIGS. 6A-6C show a flexible-membrane sleeve constructed in accordancewith the prior art (6A), and the same sleeve carried on a tissue-captureand stapling device in a relaxed (6B) and stretched (6C) condition;

FIGS. 7A-7F illustrate tissue intake into a tissue chamber having alarge tissue window where a secondary layer of tissue does not span theentire window (7A-7C); and tissue intake into a tissue chamber having alarge tissue window where a secondary layer of tissue spans the entirewindow (7D-7F);

FIGS. 8A-8C show a flexible-membrane sleeve constructed in accordancewith the present invention (8A), and the same sleeve carried on atissue-capture and stapling device in a relaxed (8B) and stretched (8C)condition;

FIGS. 9A and 9B show features of the flexible-membrane sleeve in FIG. 8A(9A) and viewed along cross-sectional line A-A in FIG. 9A (9B);

FIGS. 10A and 10B show features of the flexible-membrane sleeve in theregion indicated at C in FIG. 9B (10A), and viewed along cross-sectionalline A-A in FIG. 10A (10B);

FIG. 11 is a flow chart of the operation of the system in acquiring andfastening a tissue fold, in accordance with one embodiment of theinvention;

FIG. 12 is a plot showing the changes in device position (D) and appliedvacuum (V) during the tissue-acquisition steps in the flow diagram inFIG. 11;

FIGS. 13A-13C illustrate tissue intake into a chamber having a smalltissue window in accordance with the present invention, where asecondary layer of tissue spans the entire window; and

FIG. 14 illustrates the intake of a tissue fold into a tissue chamber inaccordance with the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The present application describes an improvement in an endoscopic devicefor forming and, optionally, fastening a tissue folds. In preferredembodiments, the device may be passed transorally into the stomach andused to plicate stomach tissue.

An anatomical view of a human stomach S and associated features is shownin FIG. 1A. The esophagus E delivers food from the mouth to the proximalportion of the stomach S. The z-line or gastro-esophageal junction Z isthe irregularly-shaped border between the thin tissue of the esophagusand the thicker tissue of the stomach wall. The gastro-esophagealjunction region G is the region encompassing the distal portion of theesophagus E, the z-line, and the proximal portion of the stomach S.Stomach S includes a fundus F at its proximal end and an antrum A at itsdistal end. Antrum A feeds into the pylorus P which attaches to theduodenum D, the proximal region of the small intestine. Within thepylorus P is a sphincter that prevents backflow of food from theduodenum D into the stomach. The middle region of the small intestine,positioned distally of the duodenum D, is the jejunum J.

FIG. 1B illustrates the tissue layers forming the stomach wall. Theoutermost layer is the serosal layer or “serosa” S and the innermostlayer, lining the stomach interior, is the mucosal layer or “mucosa”MUC. The submucosa SM and the multi-layer muscularis M lie between themucosa and the serosa.

In the disclosed embodiments of the present invention, the improveddevice is introduced into the stomach intra-orally, via the esophagus.Typically the device is equipped with an endoscope that allows thephysician to view the interior region of the stomach, and guidingstructure by which the device can be positioned at a desired targetlocation within the stomach, i.e., the region at which the device willform a tissue fold. When the device is placed against a tissue region,and vacuum is applied, a portion of the interior stomach wall is drawninwardly into the device, forming a two-layer fold or plication thatbrings sections of serosal tissue on the exterior of the stomach intocontact with one another. The disclosed device allows the opposedsections of tissue to be pressed into contact with one another, and,optionally, delivers fasteners that will hold the tissue sectionstogether until at least such time as serosal bonds form between them.Each of these steps may be performed wholly from the inside of thestomach and thus can eliminate the need for any surgical or laparoscopicintervention. After one or more plications is formed, medical devices(including, but not limited to any of the types listed above) may becoupled to the plication(s) for retention within the stomach.

The disclosed embodiments may include, in addition to a fastener forfastening tissue folds formed in the device, a feature that forms a holeor cut in a plication using the fastener-applying device. This hole orcut might be formed so that a portion of a medical implant may be passedthrough or linked to the hole/cut, or it may be formed so as to provokea healing response that will contribute to the strength of the resultingtissue bond.

In the description of the embodiments given below, the fasteners in thedevice are described as being staplers, and exemplary methods are givenwith respect to the formation of stapled plications in stomach tissue.It should be understood, however, that the fastener embodimentsdescribed herein include features having equal applicability forapplying other types of fasteners, and for applying staples or otherfasteners for purposes other than formation of plications. Morespecifically, the term “staple” is used herein to designate any type offastener that (i) can be pushed through tissue, and (ii) has one or moreleg members that when forced against an anvil are crimped to secure thefastener to the tissue and hold tissue fastened tissue fold together.The disclosed embodiments and methods will also find use in parts of thebody outside the GI system. Additionally, although the disclosedembodiment features circular stapling and cutting of a concentric hole,modifications are conceivable in which linear stapling can beaccomplished, as well as circular or linear stapling without cutting.

FIG. 2 illustrates one embodiment of a system or instrument 20 whichincludes the improved tissue-capture device, indicated at 22, forforming a two-layer tissue fold or plication. The device carried at thedistal end of a flexible shaft 24. A handle 26 at the proximal end ofthe shaft controls articulation of the device and actuation of thetissue acquisition, tissue compression, and, optionally, stapling theacquired tissue fold and or forming a hole in the fold. Vacuum and fluidsources 28, 30 in the system are fluidly coupled to handle 26 for use intissue acquisition, compression and stapling as discussed below. Thevacuum source may be the “house vacuum” accessible through a coupling onthe wall of the operating room, or an auxiliary suction pump. The systemmay include a switch 32 allowing the user to control airflow between thevacuum source and stapler. Fluid source 30 may be a single source ofdrive fluid (e.g. water, saline, oil, gas) or multiple sources, but ineach case the fluid source preferably includes two actuators separatelyused to control flow into each of two hydraulic lines (one for tissuecompression and one for stapling). Also shown is a reservoir tank 34connecting the vacuum source to the handle, for controlling the rate atwhich vacuum is applied to the tissue-acquisition device, as will bedescribed below. An endoscope 36 in the system is insertable through alumen in the shaft, and permits visualization of the plicationprocedure. The system may optionally include an overtube, such anendoscopic guide tube 38, having a lumen for receiving the shaft andattached device 22.

FIGS. 3A-3C show the distal end of the system 20, showing the connectionof device 22 to the shafts distal end 40 through a multiple-linkarticulation arm 42. The position of arm 42 is controlled by the user atthe handle, e.g., through conventional cable controls, for placing thetissue-acquisition device at selected positions and orientation withrespect to the distal end of the shaft, illustrated in FIGS. 3A-3C.

With continued reference to FIGS. 3A-3C, device 22 includes aflexible-membrane covering 44 which covers the mechanical,tissue-capture elements of the device that are described below. Thecovering and certain mechanical elements that it covers form a vacuumchamber 46 in the device. A lateral slit 48 formed in the membraneprovides an opening through which tissue is drawn into the chamberduring operation. In the embodiment shown, covering 44 is sleeve orsock, and is referred to below as sleeve 44. In the embodiment detailedbelow in Section C, sleeve 44 is formed of silicone or other elastic,biocompatible material, and at least a central portion of the sleeve issufficiently transparent to allow the user to view the interior of thetissue chamber during operation, to confirm (via endoscopic observation)that an appropriate volume of tissue has been acquired.

A. Tissue-Acquisition Device

One exemplary tissue-acquisition device 22 in the invention has themechanical components and operation illustrated in FIGS. 4A-4C and FIG.5. For purposes of description in this section, device 22 will bedescribed with respect to its mechanical elements and to the operationof those elements illustrated in these figures, it being understood thatthe device also includes sleeve 44 which covers the mechanical elementsof the device.

Device 22 is designed to have a minimum profile, shown in FIG. 4A,during insertion to the plication site; and designed to expand to theprogressively larger profiles seen in FIGS. 4B and 4C during atissue-acquisition operation.

Considering now the mechanical elements of device 22, a first orproximal member 50 includes a housing 52 and a stapler 54 that moveswithin the housing along an axis 56 extending in a horizontal directionin the figures. The extent of travel of the stapler within the housingis limited by a pair of pins 57 that travel within slots 59 formed inthe housing, as can be appreciated from the positions of the pins inFIGS. 4A and 4C. A second or distal member 58 includes a housing 60 andan anvil 62 that moves with its associated housing also along axis 56.The two members are connected by a pair of arm assemblies 64 formovement toward and away from one another, along axis 56, between thelow-profile condition shown in FIG. 4A and the fully expanded conditionshown in FIG. 4C. Each arm assembly has proximal and distal arms 66, 68,respectively, that are pivotally joined to one another at theirconfronting ends, forming elbows in the assemblies, and are pivotallyjoined at their opposite ends to the associated member 50, 58,respectively.

A pair of spreader arms 70 are anchored within housing 52 through pins57, and pivotally attached to associated assembly arms 66 at theopposite ends of the spreader arms. As can be appreciated from thefigures, movement of stapler 54 within its housing to the right in thefigures, with corresponding travel of pins 57 within slots 59, acts topush spreader arms 70 outwardly, causing arms 66, 68 to spread outwardlyand draw the two housings toward one another. At the same time, outwardmovement of arms 68 acts to move anvil 62 within its housing, toward theleft in the figures, through a scissor-arm mechanism 72 connecting thedistal ends of arms 68 to the anvil. Device 22 also has a flexiblelifter arm 78 whose opposite ends are pivotally joined to the proximaland distal members, as seen in FIG. 5. The lifter arm functions toexpand the cross-sectional area of the chamber in conjunction with theexpansion of the two arm assembles during operation of the device, ascan be appreciated from FIG. 5. In an exemplary embodiment, the vacuumchamber 46 in the device, which is defined by the arm assemblies andspreader arm, has a cross-sectional area of about 0.7-0.8 cm² in thelow-profile condition shown in FIG. 4A, and a maximum cross-sectionalarea of 7-8 cm² in the fully expanded condition shown in FIG. 4C.

Actuation of the device is by compressed fluid supplied to a pistonwithin housing 50 (not shown). This causes stapler 54 to move to theright in the figures relative to housing 50, as seen in FIGS. 4B and 4C,in turn causing the two spreader arms in the device to pivot away fromone another, and forcing the two arm assemblies toward their expandedpositions shown sequentially in FIGS. 4B and 4C. That is, actuation ofthe driving piston in the device causes the following sequence ofevents: (1) movement of the stapler within its housing along axis 56toward the right in the figures, indicated by arrow A1 in FIG. 4B, (2)movement of the spreader arms and pivotally attached arm assembliesoutwardly, away from axis 56, (3) movement of the two housings towardone another along axis 56, indicated by arrow A2 in FIG. 4B, (4)expansion of the spreader arm, and (5) movement of the anvil within itshousing to the left along axis 56, indicated by arrow A3 in FIG. 4B.When the device has executed its full extent of travel, that is, whenpins 57 reach their stop positions within slots 59, the stapler andanvil are positioned at a tissue-capture condition, seen in FIG. 4C, atwhich the confronting faces of the stapler and anvil, indicated at 74,76, respectively, are separated by a distance d. In an exemplaryembodiment, distance d is selected between 0.06-0.07 inches (e.g. foruse with staples having legs of 5.5 mm length) or 0.105 to 0.115 inchesfor 6.5 mm leg length staples. Application of additional pressure intothe hydraulic circuit will not compress the tissue any further.

As will be appreciated from Section D below, a vacuum applied to thedevice at the same time or shortly after the mechanical elements arebeing driven toward their fully expanded condition, acts to draw tissueinto the chamber. As it is being drawn in, the tissue fold expandsoutwardly, tending to fill the expanding cross section of the chamber,until the tissue chamber is fully expanded and the tissue fold iscaptured between the confronting faces of the stapler and anvil. Detailsof the device just described, and its mode or operation, are given inco-owned U.S. Pat. Nos. 8,020,741, 7,922,062, 7,913,892, 7,909,233,7,909,222, and 7,909, 219, all of which are incorporated herein in theirentirety. In particular, these patents describe in detail how staplesare and ejected through a tissue

B. Prior-Art Flexible-Membrane Sleeve

FIGS. 6A-6C show a prior-art flexible-membrane sleeve 80 of the typedisclosed in the above-cited co-owned patents, where FIG. 6A shows thedetached sleeve, and FIGS. 6B and 6C show the sleeve carried on atissue-acquisition device of the type described above and shown inpartially expanded (FIG. 6B) and fully expanded (FIG. 6C) conditions.The sleeve has a vertically-disposed rectangular opening 82 whosemidpoint 84 is close to the capture position of a two-layer fold in thetissue chamber between stapler and anvil faces 74, 76 seen in FIG. 4C.The opening has a thickened lip or ridge 86 about its periphery to serveas a reinforcing structure. The sleeve is dimensioned to cover themechanical elements of the tissue-capture device, forming atissue-capture chamber therewith, and is formed, for example, ofsilicone or other elastic, biocompatible material, and at least acentral portion of the membrane is sufficiently transparent to allowview the interior of the tissue chamber during operation.

FIG. 6B shows the condition of the sleeve as the device first begins tomove toward its expanded, tissue-capture position. As the arm assembliesand spreader arm in the device begin moving outwardly and upwardly,respectively, the opening is widened laterally, producing a verticallyoriented, ovoid opening 82′. With continued movement of the devicetoward its tissue-capture position, the opening is stretchedprogressively toward the enlarged, horizontally disposed ovoid opening82″ seen in FIG. 6C. The fully stretched opening has roughly the sameheight dimension as opening 82 in its relaxed condition (FIG. 6A), and ahorizontal dimension that typically about 70-90% the distance betweenthe elbows of the fully extended arm assemblies in FIG. 4C. Typicaldimensions of the opening in its fully stretch condition are 10-15 mm inheight (vertical dimension in the figures) and between 25-40 mm in width(horizontal dimension in the figures).

FIGS. 7A-7F illustrate schematically how the opening in the prior artsleeve can lead to unwanted tissue-acquisition effects. The figures showa cross section of a tissue intake chamber 90 in its expanded form,taken along a vertical section line in FIG. 6C, and defined by a outersleeve 92 having a fully stretched opening 94 that corresponds to themaximum vertical dimension of opening 88 in FIG. 6C, e.g., between 10-15mm. In FIG. 7A, the opening is positioned against a single layer 96 oftissue, e.g., stomach tissue, which itself is in contact with a secondlayer 98 of tissue disposed over a portion of the opening. The secondlayer may represent, for example, the wall of an organ or other tissuethat is in contact with the outer wall of the stomach over a portion ofthe sleeve opening in the figures. When a vacuum is applied to thechamber, layer 96 is drawn into and against the walls of the chamber asshown in FIG. 7B. However, since tissue layer 98 doesn't form a completeseal around the opening, no pressure differential develops between theopening and the second layer, and there is little tendency of the secondlayer to be drawn into the chamber.

However, when a second layer 98′ underlies tissue layer 96 over theentire area of the opening, as shown in FIG. 7D, drawing the targettissue layer into the chamber under a vacuum, as shown in FIG. 7E,produces a pressure differential across tissue layer 98′ that acts todraw the second layer into chamber, as illustrated in FIG. 7F. Thetissue chamber now contains two tissue folds, and applying a staple orother fastener across the folds can lead to fastening at least a portionof the second, lower fold to the two-layer inner fold. In the case of astomach plication, this would result is a plicated portion of thestomach being attached to tissue external to the stomach.

Although not shown in these figures, the force of tissue against thesides of the opening during tissue acquisition can also deform portionsof the sleeve opening itself into the chamber, with the danger thatportions of the sleeve will be become stapled to the tissue fold. Bothof the problems noted above have the potential to produce seriouscomplications to a patient undergoing plication treatment for stomachreduction.

C. Improved Flexible-Membrane Sleeve

The improved flexible-membrane sleeve of the invention is shown at 44 inFIGS. 8A-8C, where FIG. 8A shows the detached sleeve, and FIGS. 8B and8C show the sleeve carried on the plication device described above andshown in partially expanded (FIG. 8B) and fully expanded (FIG. 8C)conditions, similar to FIGS. 6A-6C. As will be discussed more fullybelow, the sleeve opening, through which tissue is drawn in tissueacquisition, is an elongate, horizontally extending slit 102corresponding to slit 48 in FIGS. 3B and 3C, and having a gapdimensioned to restrict intake through the slit of additional tissuelayers, once the two tissue layers of the tissue fold have been drawninto the tissue chamber through the slit. In an exemplary embodiment,the slit width (gap) in the relaxed condition of the sleeve shown inFIG. 8A is between 20 and 125 mils, typically about 30-50 mils, and theslit length in the relaxed condition is between about 0.5 to 0.8includes, e.g., 12-19 mm. The slit has a circumferential lip or ridge104 that helps the opening hold its shape during expansion and tissueacquisition. Also shown in FIG. 8A is a hole 103 located distal to theslit for engaging a mushroom-shaped button 105 in the anvil member inthe device (FIG. 8B), to help anchor the sleeve on the device, alongwith other sleeve-anchoring structures described below.

FIG. 8B shows the condition of the slit as the tissue-acquisition in theearly phase of tissue chamber expansion, analogous to the device in FIG.6B. As the slit is stretched outwardly along its length, the widthexpands only slightly, retaining a relatively narrow gap through whichtissue is drawn during a tissue-acquisition operation. Similarly, whenthe device is in its fully expanded state in FIG. 8C, the slit gap isstill relatively narrow, even though the slit length has been expandedto 2-3 times its relaxed state. In particular, the slit width is suchthat, even as the slit is being expanded and is fully expanded, the slitgap is dimensioned to maintain the two layers of a tissue fold incontact with one another as they are being drawn into the tissue chamberthrough the slit.

The construction of sleeve 44 is detailed in FIGS. 9A, 9B, 10A, and 10B.The sleeve is shown in exterior, head-on view in FIG. 9A, showing itssock-like construction having a closed, rounded distal end 106, an open,tapered proximal end section 108, and horizontal slit 102 midway betweendistal and proximal sleeve sections 110, 112, respectively. The verticaldimensions of the sleeve exemplified in the figures are approximately1.1 inches for each of sections 108, 110, and 112. The sleeve isattached to device 22, by pulling the sleeve over the device's distalend, until the sleeve's rounded distal end is positioned firmly againstthe distal end of the device, and the proximal tapered section of thesleeve covers at least a portion of the articulation arm 42 connectingdevice 22 to shaft 24. When so positioned, slit 102 is aligned with theelbows of the two arm assemblies in the device, and distal and proximalsections 110, 112 of the sleeve cover the distal and proximal regions ofthe chamber, respectively.

As seen in FIG. 9A, slit 102 has a central enlargement 114 that providesa point of initial tissue intake when vacuum is applied to the tissuechamber during operation. As such, the enlargement helps ensure that thetissue fold drawn into the chamber will be relatively evenly distributedfrom one side of the chamber to the other. The enlargement has a radius,in the embodiment shown, of about 75 mils.

FIG. 9B is a sectional view of sleeve 44 taken along section line B-B inFIG. 9A. The figure shows a front plate 116 having a maximum thicknesson either side of the slit, and tapering in thickness on moving awayfrom the slit distally and proximally. A typical maximum thickness inplate 116 is 90 mils, and the minimum thickness at its distal andproximal ends is about 0.25 mils, corresponding to the sleeve thicknessin regions where the sleeve has not been reinforced. The plate provideslateral support on either side of slit 102, to resist inward forces onthe slit from tissue being drawn through the slit, i.e., forces thatwould otherwise cause the portions of the sleeve on either side of theslit to be drawn into the tissue chamber.

As seen best in FIG. 10A, which corresponds to the region indicated at Cin FIG. 9B, ridge 104 in the sleeve is formed at the inner surface ofplate 116 on either side of the slit, and has inwardly projectingthickness of about 30 mils in the embodiment shown. Though not shown inthe figures, ridge 104 extends around the periphery of the slit and slitenlargement, providing additional structural reinforcement to the slit,to help the slit maintain its shape and dimensions during tissueacquisition.

As can be appreciated from FIGS. 8A-8C, sleeve 44 is stretched laterallyand compressed vertically as device 22 is moved from its low-profile toits fully expanded position. To prevent the sleeve from becomingdislodged or moved with respect to the device during operation, thesleeve has a number of structural features designed to interact withslots or projections in device 22, to anchor the sleeve on the device.With reference to FIG. 9B, one of these features is a pin or nubbin 118formed on the inner distal end of the sleeve, and intended to bereceived in a cavity 61 formed in the distal end of the device, as seenin FIGS. 4B and 5. Another feature is a pair of pins or nubbins 120projecting inwardly from opposite sides of the sleeve on either side ofslit 102. One of the nubbins is seen face on in the FIG. 9B and 10Across sections, and in side sectional view in FIG. 10B, taken along thesection line in FIG. 10A. These two nubbins are positioned to bereceived in a slot formed at the elbow in each arm assembly. Also asseen in FIG. 10A, a ring 122 formed on the back interior surface of thesleeve, immediately below the slit line, is designed to receive aprojection 81 on the spreader arm to provide sleeve anchorage to thespreader arm during tissue acquisition. Finally, the rear surface ofsection 108 has a tapered, enlarged-thickness reinforcing plate 124 withan annular groove 126 formed therein, for receiving a ring at theproximal end of the device, to help resist vertical movement of thesleeve on the device during operation.

Completing the description of what is shown in FIGS. 9 and 10, thesleeve has a pair of slots 127 formed along opposite interior sides ofthe sleeve, between proximal and distal sleeve sections 110, 112. Theslots ensure that the vacuum applied to the proximal section of thesleeve during tissue acquisition is also transmitted to the distalsection of the sleeve, even if a tissue fold drawn into the tissuechamber completely fills the chamber cross section.

The just-described sleeve is formed, e.g., by conventional molding, ofan elastic, biocompatible material, such as silicon or other elasticpolymer material. One preferred material is silicon having a durometerhardness of Shore A30±5 and a membrane thickness, other than in itsreinforced regions, of between 10-50 mils.

D. Operation of the Improved Tissue-Acquisition Device.

One example of a method for using the system 20 will next be describedin the context of formation of plications in stomach wall tissue, withparticular reference to FIGS. 11-14.

As an initial step, endoscopic guide tube 38 (FIG. 2) is advanced intothe stomach via the mouth and esophagus. The endoscope 36 is insertedinto the endoscope channel in the stapler handle (not shown) andadvanced down the lumen of the stapler handle. The tissue-acquisitiondevice and endoscope are simultaneously passed through the endoscopicguide tube towards the stomach. Once the device and endoscope reach thegastroesophageal junction region of the stomach, the position of thestapler is maintained while the endoscope is advanced further into thestomach.

The device is then advanced to the desired depth and location in thestomach, using articulation controls on the stapler handle, to placeslit 102 in the device near the target tissue. To begin tissueacquisition, the drive mechanism in the device, e.g., the hydraulicpiston in device 22, is activated, initiating the various device axialand lateral movements described in Section I above. With reference toFIG. 11, the exemplified device is actuated to move the staple and anvilmembers in the device from their low-profile position P₀ shown FIG. 4Ato a tissue-intake position P₁ at which the two members are close to,but not at, their ultimate tissue-acquisition position shown in FIG. 4C.This step is indicated at 140 in FIG. 11, and results in the elongationof the slit forming the chamber opening, as indicated at 142. The plotin FIG. 12 shows the change in spacing D between the confronting facesof the stapler and anvil members in the device as the device moves fromP₀ to P₁.over the time period t₀ to t₀.

With the device in its tissue-intake position P₁, the opening in thedevice is now placed by the physician against the region targeted fortissue acquisition, as indicated at 144 in FIG. 11. Once positioned, attime t₂ in FIG. 12, the system vacuum is initiated, as indicated at 146in FIG. 11, beginning tissue acquisition into the chamber, as indicatedat 148 in FIG. 11. In the embodiment shown, the vacuum is applied to thetissue chamber so as to increase gradually from V₀ to V_(max) over agiven time interval t₂ to t₃, typically 1-3 seconds, as indicated at 150in FIG. 11, allowing tissue to be drawn into the chamber gradually, thuspreventing abrupt stresses on the opening that might otherwise drawsleeves portions around the opening into the chamber along with thetissue. Once V_(max) is reached, at t₃ in FIG. 12, tissue continues tofill the chamber, until the tissue fold is fully drawn into the chamberat t₄, and as indicated 152 in FIG. 11.

The gradual increase in vacuum to the tissue chamber is provided by acontroller operatively connecting the vacuum source in the system to thetissue chamber. In the system described with reference to FIG. 2, thecontroller function is carried out by reservoir 34, which acts as astorage capacitor, forming and releasing a vacuum slowly as a vacuum isapplied to and released from the reservoir. It will be appreciated thatthe controller may alternatively be an electronically controlled valveor the like, which moves from a fully closed to fully opened conditionover a given time period to t₂ to t₃, e.g., 1-3 seconds.

Once the tissue fold is fully formed, at t₄ in FIG. 12, and with fullvacuum maintained to the chamber, the device is actuated to move to itstissue-capture position P₂, indicated at 154 in FIG. 11, and shown inthe plot in FIG. 12. At this position, the tissue fold in the chamber issqueezed somewhat between the staples and anvil members' faces, thussecuring it within the chamber, as indicated at 156 in FIG. 11. Thevacuum is now turned off, as indicated at 158 in FIG. 11, at time t₅ inFIG. 12, and begins a gradual decline to V₀ (FIG. 12). At the same time,the captured tissue fold may be fastened, e.g., by stapling, asindicated at 160 in FIG. 11. Finally, the device is be moved back to itsposition P₁, then P₀, as indicated at 162 in FIG. 11, and the fastenedtissue fold is released at time t₆ as the chamber vacuum is released, asindicated at 164.

The above-described timing and control of the vacuum, relative to themechanical positions of the device during operation, have been found toprovide two important benefits in tissue acquisition in the presentinvention: first, there is a significantly reduced tendency of sleevematerial around the slit to be drawn into the chamber; secondly, thechamber tends to be more completely and uniformly filled, i.e., alarger, more symmetrical tissue fold is formed.

At the same time, the horizontal slit configuration of the presentinvention has been found to largely solve the problem of secondarytissue folds being drawn into in the tissue chamber. The basis for thisimprovement can be seen from FIGS. 13A-13C, which illustrate acquisitionof a two-layer tissue fold into the device of the present invention. Inthese figures, which are similar to FIGS. 7D-7F, sleeve 44 is shown invertical cross-section in FIG. 4C, and defines a tissue chamber 126,where slit 102 in the device is indicated by gap 128 in FIG. 13A. Thefigures show the sleeve slit placed against a target layer of tissue130, e.g., a layer of stomach tissue, which itself is in contact withsecondary layer of tissue 132, e.g., an organ or tissue layer that ispressed against the layer of target stomach tissue.

FIG. 13B shows the device after activation to acquire a tissue fold fromlayer 130, by lowering the chamber pressure from P1 to P2 in thefigures. As seen in FIGS. 13B and 13C, the tissue fold has largelyclosed the gap in slit 102, preventing additional tissue material inlayer 132 from entering the chamber, even though the tissue acquisitionhas produced a pressure differential P2-P1 across the layer.

FIG. 14 is illustrates the same events in tissue acquisition, but in aless schematic form, and where the gap in the sleeve slit, indicated at132, forces the fold layers in a first into tissue layer into contactwith one another as the folded tissue 133 is drawn into the device'stissue chamber, indicated at 134. Here a secondary layer of tissue 136disposed over layer 133 is prevented from being drawn into the chamberboth lack of a gap in the sleeve slit, and because the tissue-foldlayers, when completely filling the slit gap, do not transmit thepressure differential across the gap to tissue layer 136.

Once a tissue fold has been formed and captured, the device may befurther activated to fasten the tissue fold layers, e.g., by stapling,as described in the above-cited co-owned U.S. patents.

The disclosed systems provide convenient embodiments for carrying outthe disclosed compression and stapling functions. However, there aremany other widely varying instruments or systems may alternatively beused within the scope of the present invention, Moreover, features ofthe disclosed embodiments may be combined with one another and withother features in varying ways to produce additional embodiments. Thus,the embodiments described herein should be treated as representativeexamples of systems useful for forming endoscopic tissue plications, andshould not be used to limit the scope of the claimed invention.

Any and all patents, patent applications and printed publicationsreferred to above, including those relied upon for purposes of priority,are incorporated herein by reference.

1. A method for acquiring tissue, comprising: positioning a tissuechamber of a device adjacent to tissue, wherein the tissue chamber iscovered by a sleeve that includes an opening having a length in alateral direction relative to a longitudinal axis of the device that isgreater than a width in a direction along the longitudinal axis of thedevice when the flexible-membrane sleeve is in a relaxed state; applyinga vacuum to the tissue chamber to draw tissue through the opening andinto the tissue chamber; and stretching the opening in the lateraldirection during application of the vacuum to the tissue chamber.
 2. Themethod of claim 1, wherein the width of the opening, in the relaxedstate of the sleeve, is between 40 and 125 mils.
 3. The method of claim1, wherein the length of the opening in the lateral direction, in therelaxed state of the sleeve, is 1-15 mm, and stretching the opening inthe lateral direction includes stretching the opening to a length ofbetween 25-50 mm.
 4. The method of claim 1, wherein the sleeve includessilicon having a durometer hardness of Shore A30±5 and a membranethickness of between 10-50 mils.
 5. The method of claim 1, wherein thesleeve has a reinforcing lip about the opening to aid in supporting theopening as tissue is being drawn through the opening by the vacuum. 6.The method of claim 1, wherein the tissue chamber is defined by (i)confronting faces of a proximal member of the device and a distal memberof the device that are operable to move toward and away from one anotheralong the longitudinal axis, (ii) arm assemblies connecting the proximaland distal members and that expand outwardly, along a second axissubstantially perpendicular to the longitudinal axis, as the proximaland distal members move toward one another to a tissue-capture position,and (iii) the flexible-membrane sleeve covering at least portions of theproximal and distal members and having an intermediate portion coveringthe chamber, and wherein movement of the arm assemblies outwardly, asthe proximal and distal members are moved toward one another, acts tostretch the opening in the lateral direction.
 7. The method of claim 6,wherein at least one arm assembly includes an elbow that defines a slot,and an interior surface of the sleeve includes a protrusion that isreceived in the slot.
 8. The method of claim 6, wherein at least one ofthe proximal or distal members includes a staple cartridge, and theother of the proximal or distal members includes a staple anvil.
 9. Themethod of claim 1, wherein the device includes reinforcing platesdisposed on either side of the opening to resist forces on the slit in adirection of tissue intake.
 10. The method of claim 1, wherein aninterior surface of the sleeve has one or more slots extending betweenproximal and distal regions of the device to maintain a vacuumconnection within the chamber as the tissue fold presses against aninterior surface of the sleeve during the applying step.
 11. A methodfor acquiring tissue, comprising: positioning a tissue chamber of astapler adjacent to tissue, wherein the tissue chamber is covered by aflexible sleeve that includes an opening having a length in a lateraldirection relative to a longitudinal axis of the device that is greaterthan a width in a direction along the longitudinal axis of the devicewhen the flexible sleeve is in a relaxed state; applying a vacuum to thetissue chamber to draw tissue through the opening and into the tissuechamber; and expanding the opening in the lateral direction duringapplication of the vacuum to the tissue chamber.
 12. The method of claim11, further comprising advancing the stapler into a stomach of apatient.
 13. The method of claim 11, further comprising activating ahydraulic piston to begin the step of expanding the opening in thelateral direction.
 14. The method of claim 11, wherein the staplerincludes a staple member and an anvil member, and the method furthercomprises moving the staple member and anvil member relatively towardseach other to a tissue-intake position.
 15. The method of claim 14,further comprising, after moving the staple member and anvil member tothe tissue-intake position, initiating the step of applying the vacuumto the tissue chamber.
 16. The method of claim 15, further comprising,while maintaining a vacuum level, actuating movement of the staplemember and anvil member from the tissue-intake position to atissue-capture position.
 17. The method of claim 11, wherein the step ofapplying the vacuum to the tissue chamber includes linearly increasing avacuum level.
 18. A method for acquiring tissue, comprising: positioninga tissue chamber of a stapler adjacent to tissue, wherein the staplerincludes a staple member and an anvil member spaced apart from eachother along a longitudinal axis, and wherein the tissue chamber iscovered by a flexible sleeve that includes an opening having a length ina lateral direction relative to the longitudinal axis that is greaterthan a width in a direction along the longitudinal axis when theflexible sleeve is in a relaxed state; applying a vacuum to the tissuechamber to draw tissue through the opening and into the tissue chamber;stretching the opening in the lateral direction during application ofthe vacuum to the tissue chamber and during movement of the staple andanvil members relatively towards each other; and stapling the tissue toform a tissue fold.
 19. The method of claim 18, wherein the width of theopening is dimensioned to restrict intake through the opening ofadditional tissue layers, once the tissue fold has been drawn into thetissue chamber through the opening.
 20. The method of claim 18, furthercomprising modulating a rate at which vacuum is applied to the tissuechamber.